Thread: DTC P1651 Cooling Fan Relay 1 Control Circuit

Fans are not coming on. Changed coolant sensor. With ac or heater on driver side or left hand side fan on at any temp. check engine light on after clearing twice code p1651. At 210 * with power jump to Cooling fan relay at 87 blows 15 a fuse when powered. With power to 87a cooling fan relay driver side fan on. At 210* cooling fan 1 relay 85 jumped to 86 driver side fan on and passenger side on but a little slower. At 210* CF1 relay and power to 30 both fans on passenger side or right side a little slower. CF2 relay power to 87 driver side fan on high and cf1 jumped to get LH or passenger fan on high too, nothing on LH fan and ds still runing. Tested relays all good, changed them all no difference. I need to fix for smog check this month please help. What bi directional scanner would be best for 98 pontiac and 97 suburban? I need to command fans on with scanner to check pcm? I'm thinking short on pcm to relay but i can get everything to work scratching head? Left hand is passenger side? Short at 87 on CF relay because fuse blows? PCM bad? PCM commands at with ac and heater on? I can get low speed fans on but no high speed fans if I power or jump. Only one hi speed fan on jump.

@ 210* Cooling Fan Relay pin 87=.0 v, 87a=0.0 v, 86= 12.5 v, 85= 12.5 v, 30=0.0 v.
@ 210* Cooling Fan 1 Relay pin 87=12 v, 86=12 v, 85=0.4 v, 30= 0.0.
@ 210* Cooling Fan 2 Relay pin 87=0.0, 86= 12 v, 85= 12 v, 30= 12 v.

1998 grand prix se

150,000 miles, car has engine from 1998 grand prix gt, tach doesn't work, if I don't lock steering wheel battery drains, unplugged new (Duralast from autozone lol) cts and driver side fan came on, no passenger side. Driver side is left side? Thermostat in dash is all over the place without fans? checking pcm wiring today. Pcm c1 pin 60 blk/wht continuity good ground at alternator , 56 blk/wht and 57 blk/wht no beep at ground at alternator. C1 pin 5 DRK BLU CF High Side Cooling, C1 DRK GRN CF Low Side Cooling, C1 pin 17 BLK ECTS ground, C1 56,57,& 60 pins BLK/WHT ptmc ground.

CTS yellow wire continuity to C1 pin 20 orange wire, green wire continuity to C1 pin 5 DRK BLU. I haven"t found ground BLK yet will disconnect other conection at pcm.

Do you have a printable pin out for pcm? Ok going to get an AC Delco CTS? Or Brand?

Vin 1g2wj52k4wf327322 on se car, engine came out of 1g2wp52k8wf291424 same year but gt. Thank you!!!

ACDelco CTS 213-815 or Delfi CTS TS10032?

I have spare PCM also from same car as engine.

Ground at RH fan good @ alternator, not grounding at LH fan. Does LH fan have ground?

PTMC check: ECTS harness yellow wire to clear PTMC pin 26 yellow wire continuity good. ECTS harness black wire to blue PTMC pin 12 black wire continuity good. ECTS harness green wire to blue PTMC pin 5 DRK BLU wire continuity good, also lights up blue PTMC pin 20 orange wire (battery positive voltage).

Why did i go from green wire at ECTS harness to dark blue wire at blue PTMC pin 5?

Ok @ 230* LH fan on high, 230* fan off. RH fan missing in action, low speed fans missing in action. Will check wiring and pick up new ECTS in morning. Not much to choose from local supply, maybe i should order one in.

P1651 QDM / ODM "B" - Output 1 not showing after fans kicked on twice.

ok where's the quad driver module?

Ok wire broken and shorted on CF1 Fan relay green wire at pin 85 on under hood (U/H) Electrical Center to PTMC blue pin 6 green wire. Cut both ends and ran new wire. Fans now working no error code. Replaced thermostat, ECTS, oil, oil filter, and air filter. Will address tach after smog is complete. Thank you for all your help!!!